Since a few days I am the proud owner of Fuji’s X-Pro2 system camera. Many interesting reviews have been written, but I could not find a comparison of the sensor resolution anywhere. So I just decided to use my resolution chart and do my own experiments. Together with the X-Pro2, also the X-E1 and the Canon EOS 5D Mark III were tested for comparison. This test was not about the quality of the optics, but primarily on the sensor itself. Therefore, all cameras were equipped with good standard primes (35mm, f / 1.4 on the Fujis and 50 mm, f / 1.4 on the Canon). For each camera, a diaphragm series was shot and the best (sharpest) photo was selected. The best f-stops were f/5.6 for the Fujis and f/8 in case of the Canon. Both camera systems have identical depth of field at these settings so they are directly comparable.

The following table shows the data of the cameras and lenses used in the test.

Interesting: Converted to the same ISO number the X-E1 exposes one stop too dark (at f/5.6 it has the same brightness as the Canon at f/8). I had already observed this ISO overrating in previous tests. With the X-Pro2, however, the problem is basically fixed. When adjusting the Canon’s exposure from ISO 100 to 200 and f/8 to f/5.6, the shutter time would become 1/1000s. The X-Pro2 has selected 1/800s, which is basically identical.

In the table, the resolution and the resolution limit (Nyquist limit) are given. The resolution limit can be given in lines per picture height L/PH or in line pairs per picture height LP/PH. The differ by a factor of 2 and are otherwise identical. My resolution chart used lines, print magazine tests often use line pairs.

As already pointed out elsewhere, resolutions above the Nyquist limit are completely impossible. We shall see later that all three cameras actually remain well below the limit. When some structures beyond the Nyquist limit can be observed, they are simply a matter of image defects (false alias artifacts).This can easily be explained in practice: A chessboard with say 10 x 10 fields can only hold 5 white and 5 black blocks per column - and not 6, as each kindergartner knows but some (German) "photo magazines“ apparently not.

The recording conditions:The cameras were mounted on a tripod, each meticulously centered, positioned away approximately 1.2 m from the test image. Triggering was done with the self-timer and mirror lockup (for the Canon). Auto focusing was performed before each shot on the central structure. I then picked the sharpest shot from a row of images.All photographs were taken in RAW and developed with Adobe Lightroom 6.5. Default settings were used and only white balance and exposure adjusted (+2 EV with all three cameras). I tried to activate Adobe’s lens correction on the f/1.4 - but that deteriorated resolution visibly was was quickly turned off again.Both Fuji were measured with the same lens.

The test chart shows 9 black lines that run closer to each other from right to left. The resolution limit is reached when the 9 lines can no longer be separated.It is notable that the Canon displays less contrast at its resolution limit than the Fuji. This is obviously owed to the alias filter, which ultimately acts as a blur. However, a simple twist of the contrast slider in Lightroom creates a very similar image impression (up to about the resolution limit) as in the X-Pro2 photo. This makes it clear that contrast is unsuitable as a limiting criterion for image resolution tests as it is highly dependent on software settings.

The X-Pro2 shows some clearly recognizable lines even at 3800 L/PH - but these are artifacts (aliasing), not real image content. This looks impressive at first glance and is apparently the cause of the fantasy resolution values ​​of some magazine tests. The Canon has far less of these artifacts.

The resolutions specified in the table below are based on my visual inspection of the test images. They are therefore subjective to a part, although I have taken great care to evaluate all cameras the same way. But this can not be done with better precision than some 100 L/PH (or 50 LP/PH). To this extent, the given relative resolutions are to be understood as an indication only.

In reality, despite their lack of alias filters the two Fujis can not substantially outperform the "traditionally“ equipped EOS 5D resolution wise, even though the subjective image impression is sharper at first (which can be largely compensated by a simple contrast enhancement of the Canon image).Moiré effects are not present in the images of both Fuji cameras - here, the unusual color array obviously helps really well.

Overall, the X-Pro2 has now arrived at the image quality level of very good DSLRs. The system cameras have grown up and are a good alternative even for high and highest standards of image quality. There was no visible disadvantage of the smaller APS-C sensor compared to the full-frame sensor in these tests.